The present invention pertains to vacuum batteries and more particularly to indicators for depicting the status of the vacuum battery.
Deferred action batteries are well known in the art and are used when it is necessary to have a battery with a long shelf life or when activation of the cell is desired only immediately prior to use. Such batteries are able to have a long shelf life by maintaining the battery cells in sealed condition without electrolyte. The electrolyte may be added just prior to use of the battery.
Deferred action batteries are used in artillery shells and similar devices which depend battery power for operation but require safety and reliability when not in use.
The proper deployment of artillery shells depends on a quickly deployable and known (good) battery. Fuzing arrangements are typically checked and enabled just prior to deployment of the artillery shells. Without a proper functioning battery, artillery shells may not be operational at all or may operate at an inappropriate time. Battery vacuum may be checked with a meter, but this is expensive to incorporate into each battery and is highly intensive of an operator's time when such time is critical just prior to the deployment of the artillery shells.
U.S. Pat. No. 4,699,854 issued on Oct. 13, 1987 and entitled "Multi-Option Deferred Action Battery" and U.S. Pat. No. 4,861,686 issued on Aug. 29, 1989 and entitled "Multi-Cell, Vacuum Activated Deferred Action Battery" show typical state-of-the-art vacuum batteries for us in fuzes of artillery shells.
What is required is a low cost and easily detectable indicator for showing the status of a vacuum battery.